fix: update matcher to match vuln 2.0.x versions for airflow CVE-2021-38540

Versions `2.0.x` only have `Sign In` in the body so the current matcher
does not work for the vulnerable versions. This has been tested with the
following versions: 2.0.0, 2.0.1, 2.0.2, 2.1.1, 2.1.2

Signed-off-by: ludo <controlplane@spiarh.fr>

cves/2021/CVE-2021-38540.yaml

@@ -62,7 +62,7 @@ requests:
     matchers:
       - type: dsl
         dsl:
-          - 'contains(body_1, "Sign In - Airflow")'
+          - 'contains(body_1, "Sign In")'
           - 'status_code_2 == 302'
           - 'contains(all_headers_2, "session=.")'
         condition: and